My new Koi pond is 24 ft long and 8 feet across at its widest point. It is 4 1/2 feet deep in the middle. The pond is natural (no liner). It was built two months ago and is spring fed. Roughly 200 gallons of water runs through the spill way each day. The bottom and sides are clay and I put six inches of limestone gravel on the bottom. At this point, I have no filters, pumps, or a water fall. I live in Northern Minnesota and have a decent size budget for this project. I have not decided whether to keep the pond open in the winter. I have several questions since I have no expertise.

The far wall (see picture) is 3 feet above the water level. How wide should the weir be at the top of the waterfall? Should it just plunge straight down? I have tons of natural rocks (see picture); should the face of the falls be natural rocks?

Filter/Skimmers - What should I have? I have read so much but am very confused. Should I buy a waterfall weir with a filter? What type of skimmer? Do I need a pressure filter? What about the bead filters? Should I have a UV filter?

Pump - Can whatever system I design be serviced by one large pump? What pump would you recommend?

System design - I realize I am asking for help designing a system...are there any DYI resources available?

One final question - if I decide not to keep the pond open in the winter (it gets below zero very often here) can it be designed so the take down in the fall wouldn't be much work?
I appreciate any feedback on my question.

Loads off diy on the web.
Read Alans book http://www.koikichi.com/alans-book/page-2.php
A wery good and balanced pro/con on differente aproaches on all matters in ornamental pond keeping, the rest off the siht is good in the grafics on flowpaterns (Getting in on the understanding of flow paterns) but makes you want to puke do to the banning of other solutions, by the promoter of "ERIC" (endless river in concrete) this is a good way, but by fare the only and final solution. If you have the skils tools and time it is a easy way, but go 1. generation (1. chamber empty long ras for setteling) its droped in the manufactured one only because you cant ship and sell a long empty chamber.
The biological go anoxic http://www.mankysanke.co.uk/html/anoxic_filtration.html
This woorks under the ice as the only biological filter I know off.
Iff you can opperate it on a airliftpump you have the best, cheapest investment and runing(constant) cost opperation on a pond.
You have to go DIY because this setup steal the best off differente worlds. (My opinione)A real hybrid filter.

Consider to go native on the fish speicie

I would suggest looking around on www.koiphen.com/forums

There's a huge amount of knowledge on koi ponds there

Welcome to Pond Boss, Bradchr! Glad to have you on board. Interesting question, and one that I'm not knowledgeable enough to answer, regrettably. But some folks with good input will be along to help. Beautiful looking setting you've got there!

Hey Brad, I have had two Koi ponds with water falls. I have had ponds with two pumps and one pump. I used two smaller pumps for awhile but they seem to compete with each other. I wound up using one pump for the water fall and was more satisfied. I had the pump in a skimmer box with filters and then pumped it up to a water fall box that had several filters and bags of charcol in it. It worked just fine. The secrete to keeping a clean pond, in my opinion, is to move the water as fast as you can within reason. I had a weir stone that was probably 30 inches wide that flowed on to a stair stepped water fall. My pond was only about 2 feet deep.